Bring a large pot of salted water to a boil. Add the rigatoni and cook according to package instructions until al dente, about 10-12 minutes. Drain the pasta, reserving some pasta water, and set aside.

In a large skillet over medium-high heat, remove Italian sausage from its casing and crumble into the pan. Cook for about 5-7 minutes until browned and fully cooked. Transfer sausage to a plate and set aside.

In the same skillet, reduce heat to medium and add oil if needed. Sauté chopped onion for 3-4 minutes until translucent. Add minced garlic and sauté for another 30 seconds.

Pour in crushed tomatoes. Stir and let simmer for about 5 minutes. The sauce will thicken and take on vibrant color.

Reduce heat to low and gently stir in heavy cream. Simmer for 2-3 minutes, stirring frequently until the sauce thickens.

Return the browned sausage to the skillet, mixing it into the sauce and allowing it to simmer for 2-3 minutes.

Taste the sauce and add salt and pepper as needed. Fold in the cooked rigatoni, adding pasta water if the mixture is too thick.

Serve the creamy Italian sausage rigatoni garnished with fresh basil and grated Parmesan cheese. Enjoy!